1. Field of the Invention
The present invention is directed to an apparatus for protecting computer storage equipment such as disk drives, tape drives and solid state devices from damage or destruction in the event of a fire. The invention is particularly directed to specially configured cabinetry allowing the continuous operation of computer storage equipment that will dissipate the heat normally generated during such continuous operation and will protect such equipment including the storage media in the event of a fire.
2. Description of the Prior Art
The traditional means to preserve documents and tangible things of value is to store them in a secured location. Although many types of storage locations and containers exist, the most common is the fire-resistant computer storage apparatus.
The defining characteristic of any fire-resistant computer storage apparatus is its ability to insulate the items contained within it from theft, accidental or unauthorized destruction, damage or modification. To protect against theft or unauthorized access, fire-resistant computer storage apparatus surround the protected items with barrier materials such as concrete and steel and provide complex locking systems. Similarly, to protect items from damage in the event of a fire, it is common that fire-resistant computer storage apparatus provide sealed spaces surrounded by materials having low levels of thermal conductivity. Examples of such fire-resistant computer storage apparatus include, Robbins et al., U.S. Pat. Nos. 5,295,447 and 5,377,514 and Lichter, U.S. Pat. Nos. 4,712,490 and 4,176,440.
However, these designs contemplate a preservation scheme in which a document or tangible thing is placed within a storage vault for later retrieval. Accordingly, users of the fire-resistant computer storage apparatus cannot use, access or update information contained within the fire-resistant computer storage apparatus, without opening the fire-resistant computer storage apparatus.
Increasingly, modern businesses rely upon computer and other electronically generated data as the preferred method for processing and preserving information. Data in this form is easier to capture, store, use, and exchange than data that is recorded on printed documents. Importantly, data that is stored in electronic form permits businesses to make decisions and execute transactions based upon "real-time" information that actually reflects current conditions.
As electronic commerce and other Internet transactions become more important to businesses, the need to secure, preserve and protect "real-time" electronic data grows more imperative. However, the principal forms of electronic storage, optical or disk media, tapes and solid state devices are all relatively vulnerable to casualty damage and are particularly sensitive to damage through exposure. Environmental extremes such as fire, heat, or contamination can damage these devices and can result in the corruption or wholesale loss of vital business information. Accordingly, businesses have developed a variety of approaches to protect their data. One popular solution involves the purchase of additional, and duplicative, storage arrays that are located in separate places. However, the use of redundant arrays is costly and increases the maintenance burden associated with data storage.
Another solution involves periodically "backing up" or preparing a copy of important data on tapes, disks or portable solid state devices. The copy is then stored in a location where it is less likely to be damaged. Traditional fire-resistant computer storage apparatus are often used to store such "back up" copies and provide excellent protection against fire damage, contamination, theft or mutilation.
However, the preparation and storage of "back-up" information is a time-consuming task. Further, such "back-up" copies depict the contents of the business' electronic database as of the moment that the "back up" is made. In the event that that a business' normal storage media is damaged or destroyed, the business will be unable to recover, electronically, any data recorded by the business between the time that the "back up" is made and the time that the storage media was damaged.
This creates a conflict for business owners. The owner must balance the costs associated with the risk of lost data against the costs of making and securing "back ups." Typically, this balance results in a periodic "back up" system in which "back ups" are made on a monthly, weekly or daily basis. Under this system, the owner inherently accepts the risk that important information may be lost if significant transactions occur between the time that a backup is made and the time that the owner's data storage media is damaged or destroyed.
Accordingly, to reduce the costs of "back ups" and to lower the risk of lost data, what is necessary is a storage cabinet that preserves and protects electronic data storage devices from accidental, environmental and other damage yet allows the data storage device to operate in real-time.
Meeting this necessity has proven difficult, as there are two principal technical challenges that must be overcome. The data storage device must have adequate protection against thermal and environmental extremes. This typically involves locating the device inside a container or cabinet which is equipped with an inner space. This inner space is surrounded by a thermal insulator and sealed against the possibility that heated gasses or environmental contaminants will enter. In order to provide appropriate thermal protection, it is necessary that the thermal insulator be a poor thermal conductor.
When an active component such as a disk drive is stored in such an inner chamber, the drive itself creates heat that must be dissipated. However, a sealed thermal insulator surrounds the drive. Thus, the thermal insulation used to protect the drive from external heat damage also works to prevent dissipation the heat generated by operation of the drive itself. If the heat is not adequately dissipated, the temperature in the inner space will rise and potentially damage the storage device. Thus, a first technical challenge is to design a thermally insulated container to protect a data storage device while still providing an adequate mechanism for the dissipation of the heat generated by the device.
This problem has been addressed in various ways by the prior art. One solution provides cabinetry for data storage media that features an integral air conditioning system to control the temperature of the area enclosing the data storage device. Another solution involves cabinetry containing apparatus to defeat the insulation during normal conditions.
Branc et al., U.S. Pat. No. 4,585,303 and Koneko et al., U.S. Pat. No. 4,495,780 both disclose cabinetry that use environmental controls to maintain the temperature of active electronic devices containers within the cabinet. Branc et al., discloses a disc drive isolation system including an environmental control involving a thermoelectric heat pump and fan. Temperature and humidity sensors located near the disk drive actuate the heat pump to regulate the thermal conditions inside the cabinet. Similarly, Koneko et al. discloses the use of a cooling system to cool electronic devices housed within a hermetically closed chamber.
Cabinetry featuring environmental control systems like those disclosed in Branc et al. and Koneko et al., are expensive to buy and costly to maintain. More importantly, these systems, in themselves, create new risks that a data storage device stored within the cabinetry will be damaged resulting in lost data. Because these cabinets require active thermal regulation to control temperatures in the area surrounding the storage device, a loss of that active thermal regulation will result in increased temperatures and damage to the storage media. It is only possible to avoid such a result, when using these cabinets through exceptional maintenance and service practices, or by designing a system that automatically shuts down if the temperature exceeds a set limit. This latter alternative is unacceptable in real time business systems.
Kikinis, U.S. Pat. No. 5,623,597 presents two alternative systems, an "active" system and a "passive" system, for protecting a data storage device. In the "active" system, a data storage device is mounted onto a heat sink structure within a fireproof enclosure. A heat transfer system involving a radiator is connected to the heat sink and circulates a coolant through the wall of the fireproof enclosure. A thermostat controller is mounted on the outside of the wall to disable the heat transfer system in the event of a fire.
In the "passive" system, a data storage device is similarly attached to a heat sink. In this system, however, thermal-insulating material has a gap that permits the heat sink to be urged into contact with the exterior metal surface of the cabinet by a set of springs. This allows for the discharge of the heat generated by the data storage device during normal operation. If the thermostat detects fire, it releases a pressurized liquid insulting material into the space between the metal surface and the heat sink. This separates the heat sink from the metal surface of the fire-resistant computer storage apparatus and provides a degree of insulation.
Both embodiments of the Kikinis system create a risk of failure in that the key thermal management component, the thermostat may fail. In the event of a failure of the thermostat, heat from a fire will be conveyed directly to the data storage device. This will be likely to have catastrophic consequences for the data storage device.
In addition, the "passive" embodiment of this system involves the increased risk of failure associated with the use of a pressurized insulation injection system that must stay fully charged until it is necessary to activate. Alternative versions of this "passive" embodiment include the use of electrical, mechanical, and electromechanical means to separate the heat sink from the metal exterior of the fire-resistant computer storage apparatus. All of these systems have the potential to fail to operate, particularly if they are unused for a period of months or years. To lower these risks, the thermostat, heat transfer system, insulation injection system, and separation means must also be maintained and tested periodically. Thus, what is needed is a cabinet to protect an operational data storage device that is fully passive, requires no maintenance, yet provides adequate thermal protection.
A second technical challenge confronting the designers of such a cabinet is the challenge of permitting electrical and data cables to pass through the insulation without compromising the thermal integrity of the data storage device. There are two ways in which this thermal integrity can be compromised. First, most electrical and data cables are made of metal materials because of their electrical conductivity. However, the metal used in these cables tends to also be a good thermal conductor. Thus, there exists the risk that the cables will become heated by exposure to a fire outside of the cabinet and will convey this heat to damage a data storage device located within the cabinet. Second, the passageway itself can provide a pathway permitting the entry of heated gasses.
Branc et al., Koneko et al. and Kikinis all inherently require that electrical and data cables have a passageway from the exterior of the cabinet into the thermally protected area about the electronic storage device. However, these fail to identify any method for protecting the data storage device from the risks of thermal damage associated with the cables and passageway.
Thus, what is needed is a system that is fully passive, requires no maintenance, provides adequate thermal protection for a stored data device and provides an entry for passing electrical and data cables through the thermal insulation without exposing the data storage device to an enhanced risk of thermal damage created by externally heated data cables of gasses.